II. A STUDY OF PLATONIC TERMINOLOGY. BY G. VAILATI. RESEARCHES relating to the introduction and the changes in meaning of the technical terms of philosophy and logic present a striking contrast to analogous researches about the terminology of the physical sciences. Whereas, in the latter,, the introduction of a new term, or of a new meaning for a. term already in use, is generally due to the need of giving expression to some new idea or distinction, or of giving a. name to some new object hitherto unknown ; in the field of philosophy, on the contrary, the chief impulse to transforma- tions of nomenclature arises from a totally different cause, viz. : from the inability of the terms referring to the more abstract ideas, which occur in philosophical researches, to- retain for long the precise and well-defined meaning origin- ally attributed to them, and from their tendency to become imbued with associations incompatible with the function assigned to them by those who introduced them. That is, the majority of the changes in philosophical nomenclature are due to the need of substituting, for ex- pressions that have become unfit to express a given idea, clearly and with sufficient definiteness, other expressions in. which the same idea or the same distinction is characterised in a form less apt to give rise to confusions or misunder- standings. This is not the least important of the causes that combine to bring about the result that the contribution made by each philosopher, the advances and the improvements represented by his work, compared with that of his predecessors, are more difficult to recognise and appraise than the degree of origin- ality of scientists properly so-called. The historian of philosophy is far more exposed than are the historians of the sciences to the danger of mistaking for new opinions and discoveries what is only a new expression of ideas and distinctions recognised long ago, and of seeing